Field of the Invention
The present disclosure relates to a copying machine, a multifunctional peripheral and the like, particularly, the present disclosure relates to processing technology for treating paper jamming in the same.
Description of the Related Art
In an image forming apparatus, a sheet stored in a sheet feeding cassette is taken in. While conveying the sheet, the image forming apparatus forms an image on the sheet. At this time, paper clogging (hereinafter referred to as “jam”) is sometimes caused on a conveying path. Depending on a stop position of the sheet at the occurrence of the jam, a user sometimes finds it difficult to perform jam processing. For example, this includes a case when the jam occurs immediately after the sheet is fed from the sheet feeding cassette and a leading edge of the sheet hardly comes out from the sheet feeding cassette. In this case, even if the user opens a door provided on a side surface of the image forming apparatus main body to remove the sheet, a user's hand is difficult to reach the sheet, which makes it difficult to perform the jam processing.
A method to convey a sheet to a position where the jam processing is easily performed at an occurrence of the jam is known. However, the sheet cannot sometimes be conveyed to a position where the jam processing is easily performed due to collision between sheets caused when a space with a preceding sheet which has stopped at the occurrence of the jam is narrow. An image forming apparatus as disclosed in Japanese Patent Application Laid-open No. 2012-78604 discloses a technology for forcibly conveying a sheet by a predetermined amount in accordance with a size and a type of the sheet after the door provided on a side surface of the image forming apparatus main body is opened at an occurrence of a jam. By delivering a leading edge of a subsequent sheet in an open space of the opened door, even in a case where the space with the preceding sheet is narrow, the user can easily perform the jam processing.
Some image forming apparatuses comprise a fixing conveyance unit in which a conveying unit for conveying a sheet is integrated with a fixing device for fixing an image on the sheet. When the jam occurs in a conveying unit part of the fixing conveyance unit, by opening a front door provided on a front surface of the image forming apparatus main body and drawing out the fixing conveyance unit, the sheet can be removed.
A conveying path of the fixing conveyance unit is connected to a conveying path provided in the image forming apparatus main body. The conveying path provided in the image forming apparatus main body includes a conveying path for conveying the sheet to the fixing conveyance unit and a conveying path for delivering the sheet outside the image forming apparatus from the fixing conveyance unit. The conveying path for conveying the sheet to the fixing conveyance unit includes a conveying path for conveying the sheet fed from the sheet feeding cassette to the fixing conveyance unit and a conveying path for conveying the sheet fed from an external optional deck to the fixing conveyance unit. When the jam occurs between the conveying path of the fixing conveyance unit and the conveying path of a main body frame of the image forming apparatus, the jammed sheet straddles between the conveying path of the fixing conveyance unit and the conveying path of the image forming apparatus main body, with a portion of the jammed sheet being on the conveying path of the fixing conveyance unit and the other portion of the jammed sheet being on the conveying path of the image forming apparatus main body. When the fixing conveyance unit is drawn out in this state, the sheet is torn into parts, in particular, a part remaining on the conveying path of the image forming apparatus main body and a part on the conveying path of the fixing conveyance unit. In the following, a state in which the sheet is torn in this manner is referred to as “sheet torn off”. Due to “sheet torn off”,the sheet is torn, which creates a sheet piece. Removing the sheet piece is not easy. The sheet piece which is not removed but remains causes a new jam.
There are some patterns in which the jam occurs between the conveying path of the fixing conveyance unit and the conveying path of the main body frame of the image forming apparatus. For example, the jam occurs when, in the jam processing performed when a plurality of sheets is overlappingly conveyed, only one sheet can be taken out. The jam also occurs when a sheet is retained due to an instantaneous disconnection of a power and when the sheet cannot be grabbed at the time of the jam processing and the like. There is a method to forcibly deliver the jammed sheet to an exclusive delivery tray (escape tray, purge tray), however, this has a problem in terms of cost. Thereby, an image forming apparatus capable of easily performing the jam processing is desired.